Multilateral well technology allows an operator to drill a parent wellbore, and subsequently drill one or more lateral wellbores that extend from the parent wellbore at desired depths and angular orientations. For many well completions, such as offshore deepwater wells, multiple lateral wellbores are drilled from a single parent wellbore in an effort to optimize hydrocarbon production while minimizing overall drilling and well completion costs.
Briefly, drilling a multilateral well first requires that the parent wellbore be drilled and at least partially completed by lining the parent wellbore with a string of casing or other type of wellbore liner and subsequently securing the casing to the wellbore with cement. The casing serves to strengthen the parent wellbore and facilitate isolation of certain areas of the surrounding subterranean formations for the eventual production of hydrocarbons. A casing exit (alternately referred to as a “window”) is then created in the casing at a predetermined location to initiate the formation of a lateral wellbore. The casing exit is formed by running a whipstock assembly into the parent wellbore and securing the whipstock assembly at the predetermined location. The whipstock assembly is then used to deflect one or more mills laterally to penetrate (i.e., cut through) the casing and form the casing exit. Once the casing exit is formed, a drill bit can then be inserted through the casing exit to drill the lateral wellbore to a desired depth, and the lateral wellbore can then be completed as desired.
Drilling and completing multilateral wellbores can be a costly and time-consuming process that requires multiple “trips” into the parent wellbore to complete various completion tasks. Moreover, entering a drilled and completed lateral wellbore for post completion downhole operations can also require multiple trips into the parent wellbore. Accordingly, well operators are always looking for ways to reduce the number of downhole trips and thereby save time and expense.